The Iss's answers

Bundibugyo Ebola virus outbreak, here's what to know: from risks to contagion

The Istituto Superiore di Sanità answers numerous questions on the rare variant of the virus for which the WHO has declared a state of emergency

by Letizia Giostra

19 May 2026

2' min read

Translated by AI

Versione italiana

2' min read

Translated by AI

Versione italiana

It was on 5 May when the World Health Organisation (WHO) was alerted to mysterious deaths in Mongbwalu, in the Democratic Republic of Congo. After only a few days, a rare variant of Ebola was confirmed in as many as eight samples. It is Bundibugyo, a virus for which there is no vaccine and no specific therapy.

Confirmation of the outbreak then came from Uganda's Ministry of Health after the death of a Congolese man on its territory. Following the dramatic increase in cases, the WHO has therefore determined that the disease constitutes a public health emergency of international concern, thus declaring a state of emergency globally, but does not mean it will necessarily follow up with a pandemic. The latest bulletin from the WHO indicates 30 confirmed cases, but there are 500 suspected cases with 131 possible deaths.

Everything we know about Bundibugyo

Although the name of this virus may be new, there have been two other outbreaks in the past, and always in the same places: the first in Uganda and the next in the Democratic Republic of Congo, in 2007 and 2012 respectively, with a mortality rate of between 30% and 50%. As for the incubation period, it varies from 2 to 21 days. Those who have contracted the virus are infectious only after the first symptoms appear.

The most common ones are fever, fatigue, muscle pain, headache and sore throat. In the worst cases, patients may also experience gastrointestinal disorders, organ dysfunction and haemorrhagic manifestations. Early diagnosis can save the infected person from a worsening of the disease, but the first symptoms can often be mistaken for a common flu and the delay in diagnosis, in these cases, can be fatal.

How the virus is transmitted

Bundibugyo is a severe and often fatal variant of Ebola and is likely to originate from fruit bats. The virus can only pass from animal to human through close contact with blood or secretions and spreads from person to person in the same way. Transmission is amplified in healthcare settings when infection prevention and control measures are inadequate. The same happens when contact is made with the deceased during burial of the infected person.

The risk for unaffected countries

According to the European Centre for Disease Prevention and Control, the probability of infection for EU residents or all travellers to Africa is considered low.

The indications for non-affected countries

It remains to be clarified how non-affected countries should behave. For the Higher Institute of Health, no country should close its borders or impose restrictions. The risk is that people may opt for uncontrolled borders, thus increasing the likelihood of the disease spreading.

National authorities should liaise with airlines and other transport and tourism sectors, while states should provide travellers to affected and at-risk areas with all necessary information and facilitate the repatriation of their nationals who have been in contact with the virus. Finally, the Institute does not consider it necessary to subject passengers returning from areas under observation to entry controls at airports or other points of entry, except outside the affected region.